#include <fstream>
#include <vector>
using namespace std;

ifstream fin("ciclueuler.in");
ofstream fout("ciclueuler.out");

const int N = 100001, M = 500001;

int n, m, viz[M];
vector<int> ad[N], sol;
vector<pair<int,int>> muchii;

void dfs(int nod)
{
    while (!ad[nod].empty())
    {
        int v = ad[nod].back();
        ad[nod].pop_back();
        if (!viz[v])
        {
            viz[v] = 1;
            dfs(muchii[v].first ^ muchii[v].second ^ nod);
        }
    }
    sol.push_back(nod);
}

int main()
{
    fin>>n>>m;
    int x,y;
    for(int i=0;i<m;++i)
    {
        fin>>x>>y;
        ad[x].push_back(i);
        ad[y].push_back(i);
        muchii.push_back(make_pair(x, y));
    }
    dfs(1);
    for(int i=0;i<sol.size()-1;++i)
        fout<<sol[i]<<" ";
    return 0;
}